The present invention relates to a weighing apparatus. An embodiment of the present invention is advantageous for automatically weighing small samples generally disposed in containers in an array of racks. The invention also relates to weighing systems that provide flexibility and convenience in generating and transforming a variety of data sets associated with measurements accomplished using the weighing apparatus.
Recently, the proliferation of combinatorial libraries in high throughput synthesis and screening (HTS) programs have led to an ever increasing emphasis on automation. The ability to prepare and test a large number of compounds quickly can provide a competitive advantage. Thus, automated preparation and evaluation has become a key process in lead discovery.
The recent explosion in the number of compounds available for screening, and the expected increase in compounds with the development of automated chemical synthesis, has meant that a large number of pharmaceutical and other chemical companies are in need of automated weighing of such compounds. However, several difficulties have been encountered in attempts to provide a fast, efficient, and cost-effective solution to the problem of automatically weighing large numbers of small samples.
Proposed solutions which simply implement robotic methods to remove and replace samples from racks to facilitate weighing present significant problems. Robotic fingers have difficulty in grasping individual samples for removal from among an array of closely placed samples in a rack. Certain devices function only with flat bottom containers, which are more difficult to return to the rack after weighing. Misplacement during return may result in spilling of the sample contents, or breakage of one or more samples (possible leading to contamination of on e or more samples).
A major difficulty unsolved by current devices is the lack of speed when weighing a large number of samples. Current devices generally employ a robotic sample transfer assembly, which retrieves a sample from an array, transfers the sample to a separate balance, and then returns the sample container to a particular position in a holder, such as a test tube rack. Although some such systems may have the ability to identify the particular sample, and associate the sample with the measurement taken to enable later data recordation and processing, systems currently employed require a large amount of inefficient and time-consuming movement. The sample must be plucked from an array, moved to the balance, retrieved from the balance, moved back into position relative to the array, and returned to the sample""s original position. Thus, having the balance a considerable distance from the actual sample position within an array leads to a great deal lost time in moving each sample to and from the balance.
Current devices also handle a relatively limited number of samples during each run. It would be advantageous to provide an automated system which is capable of handling a larger number of samples than those devices currently available.
Accordingly, it is one object of the present invention to provide an automated weighing system which handles a larger number of samples per run than currently available devices. It is also an objection of the invention to accomplish weighing of a large number of samples in less time, and with increased handling efficiency and reliability. Additionally, another object of the invention is to provide a weighing system allowing increased control of an automated weighing apparatus, and increased versatility in data collection, storage and transformation.
The present invention provides a solution to many current problems associated with automated weighing of large numbers of samples. One advantage is that the overall movement of individual samples to accomplish the weight measurement is minimized. This reduces the time required, and reduces the likelihood of malfunctions such as breakage of sample containers and/or contamination of samples.
Accordingly, in one aspect the invention relates to an automated weighing station comprising a support frame, a balance secured to the support frame, a sample handling assembly operably connected to the balance and secured to the balance, a moveable carrier for moving samples into position beneath the sample handling assembly, a lift assembly positioned beneath the moveable carrier and the sample handling assembly for lifting samples into position to be accessed by the sample handling assembly, and a control system for controlling the sample handling assembly, the lift assembly, and the moveable carrier in a coordinated manner, and for storing weight measurements of individual samples. The control system also provide a user interface.
In another aspect, the invention relates to a method of weighing multiple individual samples comprising moving an ordered array of sample containers beneath a stationary sample handling assembly, elevating at least one sample container, reversibly securing the at least one sample container to a gripper assembly of the stationary sample handling assembly, and returning the at least one sample container to the ordered array after a weight measurement is taken, wherein the gripper assembly is connected to a balance, and is disengaged from other components of the sample handling assembly while the weight measurement is taken.
In yet another aspect, the invention relates to a weighing system for automated weighing of samples comprising a support frame; a balance secured to the support frame; a sample handling assembly operatively connected to the balance and secured to the balance; a moveable carrier for moving samples into position beneath the sample handling assembly; a lift assembly positioned beneath the moveable carrier and the sample handling assembly for lifting samples into position to be accessed by the sample handling assembly; and a data handling system for storing and processing of weight measurements of the samples.
The invention provides many of the benefits described herein by virtue of the close association of the sample handling assembly, including the gripper assembly, with the balance where the weight measurement is taken. The benefits provided by the invention are described in greater detail below.